1. Field of the Invention
The present invention relates to a semiconductor device and, more specifically, a high speed metal oxide semiconductor field-effect transistor (MOSFET) having a novel structure and a process for manufacturing the same.
2. Description of the Related Art
Semiconductor integrated circuits are used in various devices as high speed logic devices and high capacity memories, but research is still underway to increase the speed and lower the power consumption of semiconductor devices.
In one conventional high-speed n-channel MOSFET, formed in a thin film semiconductor layer of a semiconductor-on-insulator (SOI) structure, the speed of the MOSFET can be increased by precise control of the channel region by the gate voltage, compared with that of a MOSFET formed in a bulk semiconductor (substrate).
However, in the conventional structure, the control of the channel is not complete because the channel is controlled only by a gate electrode on an upper side.
In another conventional MOSFET, one having an XMOS structure, the channel is controlled from both sides by the upper and lower gate electrodes and so the control of channel is complete in comparison with the case of the first structure. Nevertheless, the process for forming this is difficult.
The present invention was made in view of the above problems and has as objects thereof to provide a high speed and highly functional MOSFET having a novel structure and a process for manufacturing the same.